Clutch bleeding issues...

[Sirius815]

Alright, I'm not an idiot...(I don't think). I've never had a problem bleeding brakes, but this clutch is kicking me for some reason.

My CR feels as though its dragging quite a bit as if the clutch was disengaging all the way, so I thought I may have some air in the lines. I've bleed them before, which is not a fun experience... I was using the manual method, squeeze lever, crack open bleeder, close bleeder, work the lever, rinse&repeat.

My question is - why is there so little fluid coming out of the bleeder? (Yes it's open all the way). We did this about ten times and the level in the reservoir barely moved. I also tried reverse bleeding the thing but I can't seem to get fluid to the top... Have there been master cylinder failures that would cause this?

Ben K.

 

[mrlogix]

hate to say it, but I would be tempted to pull the hose and see if there is some kind blockage. Also if the master cylinder needs rebuilt the pressure maybe bleeding past the piston in the MC. Just my .02

 

[Cosworth]

Does it have the Oberon or ebr clutch yet? Id check for scarring on the cylinder while you are in there

 

[Cooter]

Ya, sounds like a blockage somewhere. A couple things to check that would do that are...

A partially plugged bleeder. Take it out and poke or micro drill it clean, then blow out the debris. As a bonus, wrap a tiny bit of teflon tape around the threads being careful not to cover the hole. I KNOW the bleeder doesn't seal on the threads but when you have to vacuum bleed it later, it won't suck air past the threads and give you a false reading.

A plugged bypass hole in the M/C. It's the TINY hole. Sometimes a stainless wire will unplug it, but since no one changes their fluid as ofter as they should (read never) the debris can be super hard and you'll need to micro drill it by hand. Don't worry about making it slightly larger it won't hurt anything, and the M/C piston and o-ring should be plenty clear of the hole so the drill will go right past it.

Once you get flow, if it still won't bleed then check the angle of the M/C. My Hulk hands make me rotate the levers so far down on my CR Clubmans that there will be air trapped in the top of the M/C bore. I need to loosen the Clutch M/C on the bars and rotate it up. I see air bubbles come out right away.

Still won't bleed? While holding the clutch lever, loosen and tighten the banjo fitting at the M/C.

Sorry for the novel

 

[Sirius815]

Thanks for confirming my suspicions guys! Since the CR is still relatively new to me and I (thankfully) haven't needed to do much maintenance on it I wasn't sure if there was something I was missing, especially after looking through the service manual and searching about "normal" or common problems with the clutch.

 

[Cooter]

Let us know what it was. Got to get ya back on the road!

 

[Sirius815]

Oh I'm not off the road. I still have my 12R Actually, I rode it today as it works, but it just seems like the clutch drags in first (with lever pulled in). Does anyone else's 1125 (R or CR) want to lurch forward when starting? It seems to be worst then. After the motor is spinning it doesn't want to creep forward by itself anymore, but definitely during cranking. I have started to put in neutral before cranking.

Tonight I took the line off at the clutch cover and found that fluid wouldn't drain very well from the master down. I'm leaning towards rebuilding the master. It took forever to bleed the clutch again. The other thing I did was go ahead and adjust the clutch lever to "1", giving me some more stroke, which seems to have helped some. I normally have the lever set on "3" as I have small hands.

I'm trying to think back at all the things the PO told me and what was in the ad (which my dumb self did not keep a copy of). I want to say the clutch weep issue was taken care of previously, which hopefully means an updated unit with no issues. I don't yet want to open up the clutch cover as I'm not wanting to have all that down time yet.

 

[Sirius815]

Last night I rebuilt the master. The old parts didn't look bad, but that's one possible culprit down. The d@mn thing still wouldn't bleed (no fluid movement), so I came to the conclusion it must be (or in addition to the master needing a rebuild) a clogged line like mentioned earlier. Replaced the line temporarily with the longer line for the high bars - voila, bled pretty easily. WTF! Okay - just for grins I drained all the fluid yet again (I think this is the 4th or 5th time now) and put the "old" short line back on. And...we're good?! It bled easily, no issues. Pushing the bike in gear with clutch pulled seems to be better than before and upon a quick start while in gear she didn't want to surge forward like before.

I'll keep an eye on it, feel for it, all next week and see how it goes. I'm hoping problem solved, although I may still choose to put in the Oberon piece.

 

[Sirius815]

So, I just noticed that there is a discrepancy between the parts that came out of the master cylinder (and the rebuild kit) and the service manual. The master cylinder contained, and the rebuild kit came with, a silver washer that sits underneath the circlip to hold the piston in. The service manual does not show it and does not make a mention of it...I wonder if this washer can be left out to get extra stroke out of the master cylinder piston?

 

[mrlogix]

if removing the hose and replacing it back on again cured it, and there was no physical blockage (foreign material) in that hose, I am guessing that there was an air pocket trapped in some manner in the hose itself. Now before someone flames me for that statement let me go on. The routing of the hose and position of the bleeder screw in the caliper is to promote trapped air to continue to the caliper and by differences in gravity become trapped in the area of the bleeder screw. As an engineer I have learned over the years that gravity doesn't always work when incorporated in the design of an object or process. I have my assed kicked before by gravity not doing what it should all the time. If an air pocket traveling through the hose does not reach the caliper because the fluid displacement volume is less than the volumetric capacity of the hose, the air pocket (bubble) can get trapped going back and forth between the MC and the caliper or hydraulic cylinder. Doesn't happen this way often but does happen. If the line volume isn't drained from opening the bleeder, the air bubble doesn't ever get to the caliper/bleed screw. This is why you have to go through several sequences of the bleeding procedure. In very rare circumstances even after several bleeding sequences there can still be air trapped in the line and require line removal and re-install and start the bleeding procedure all over again to move enough volume to get all the trapped air out. This why I asked you to remove the line and verify blockage, kills two birds with one stone.

That's my story and I am sticking to it. :tongue-new:

 

[Sirius815]

I like the reasoning and won't discount it as being a possible contributor in my case. Any thoughts on the master cylinder parts assembly?

 

[mrlogix]

The volumetric displacment achieved by leaving it out to increase piston travel will be minimal

 

[Theycallmecrash]

He was referencing the brake master which uses a different retaining clip than the clutch, mistake happen

 

[mrlogix]

Thanks for the catch Crash :black_eyed: The logic still applies just substituting the caliper instead of the clutch cylinder. Both are technically cylinders, just with different work being performed by the hydraulics. Didn't mean to be confusing. Was listening (had to appear like I was) to the ol' lady while typing.:angel:

 

[Theycallmecrash]

That just reminded me of this
http://www.buellxb.com/forum/showthread.php?35093-She-just-gave-me-attitude

 

[mrlogix]

^^ LMFAO, exactly what was happening

 

[Sirius815]

Yeah - that was my mistake. I saw the diagram thinking it was the clutch. On the other hand, both masters perform the same function - displace fluid to cause movement. Not sure why the design (washer versus no washer) is different.

Thanks guys!

 

[mrlogix]

could be like crash said brake master which uses a different retaining clip than the clutch

 

[Sirius815]

The clip is definitely different according to the diagram. I wonder if the one from the brake master could be used in the clutch with no adverse effects. Of course as you mentioned, the difference in displaced fluid is essentially nil.

 

[mrlogix]

I would say it would depend on the contact area of the retaining clip with the surface that it stops on in the MC. The washer would help distribute the force evenly around the retaining clip. Use your best judgement.